MatthewKosloski

SSH Cheatsheet

You know how it goes. SSH is something that nearly every developer uses every day, however, they only set it up a couple of times and then forget about it. And whenever you need to authenticate with SSH again, you just look up how to do it, never remembering how to do it because why would you?

SSH Protocol

What is it?

SSH, which stands for Secure Shell, is a network protocol that enables a client to securely connect to a remote server. All user authentication, commands, outputs, and file transfers are encrypted to protect against attacks in the network. It is a more secure alternative to non-protected login protocols such as FTP.

guizmaii

The default formula use by AWS RDS to calculate the max_connections parameter is: LEAST({DBInstanceClassMemory/9531392},5000)

But It's hard to find the exact value of DBInstanceClassMemory.

So, here are the values I got when I ran the SQL commmand: show max_connections; in some RDS instances:

Instance type	RAM (GB)	max_connections
db.t2.small	2	198
db.t2.medium	4	413

alainlompo

import static org.mockito.Mockito.*;
import java.util.HashMap;
import java.util.Map;
import org.junit.Test;

public class MockitoSpyExample {
  @Test
  public void spyExample_nominal_case_Test() {
    Map<String, String> hashMap = new HashMap<String, String>();
    Map<String, String> mapSpy = spy(hashMap);

IMcPwn

// Turn on Developer Mode under User Settings > Appearance > Developer Mode (at the bottom)
// Then open the channel you wish to delete all of the messages (could be a DM) and click the three dots on the far right.
// Click "Copy ID" and paste that instead of LAST_MESSAGE_ID.
// Copy / paste the below script into the JavaScript console.
// If you're in a DM you will receive a 403 error for every message the other user sent (you don't have permission to delete their messages).

var before = 'LAST_MESSAGE_ID';
clearMessages = function(){
	const authToken = document.body.appendChild(document.createElement`iframe`).contentWindow.localStorage.token.replace(/"/g, "");
	const channel = window.location.href.split('/').pop();

evanwill

How to add more to Git Bash on Windows

Git for Windows comes bundled with the "Git Bash" terminal which is incredibly handy for unix-like commands on a windows machine. It is missing a few standard linux utilities, but it is easy to add ones that have a windows binary available.

The basic idea is that C:\Program Files\Git\mingw64\ is your / directory according to Git Bash (note: depending on how you installed it, the directory might be different. from the start menu, right click on the Git Bash icon and open file location. It might be something like C:\Users\name\AppData\Local\Programs\Git, the mingw64 in this directory is your root. Find it by using pwd -W). If you go to that directory, you will find the typical linux root folder structure (bin, etc, lib and so on).

If you are missing a utility, such as wget, track down a binary for windows and copy the files to the corresponding directories. Sometimes the windows binary have funny prefixes, so

janikvonrotz

SQL languages

DDL is short name of Data Definition Language, which deals with database schemas and descriptions, of how the data should reside in the database.

DML is short name of Data Manipulation Language which deals with data manipulation, and includes most common SQL statements such SELECT, INSERT, UPDATE, DELETE etc, and it is used to store, modify, retrieve, delete and update data in database.

DCL is short name of Data Control Language which includes commands such as GRANT, and mostly concerned with rights, permissions and other controls of the database system.

Datatypes

Text types

joseluisq

Add Git Branch Name to Terminal Prompt (Linux/Mac)

Open ~/.bash_profile in your favorite editor and add the following content to the bottom.

# Git branch in prompt.

parse_git_branch() {

rgreenjr

-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%'